1. Field of the Invention
The present invention generally relates to optical disc recording, and more particularly to method for adjusting write power when recording optical disc.
2. Description of the Prior Art
Optical disc recorders, such as CD−R and DVD−R, are very popular in current information technology applications. In the recording process, or so-called burning process, one optical pickup head of the recorder emits a laser beam projecting at a plurality of tracks on the surface of optical disc for recording data. The power of the emitted laser beam is referred as a write power. When the write power is too high or too low, the recording quality of the optical disc is downgraded. Usually, conventional recorders read some parameters indicating the recording quality (referred as write quality parameters), such as Beta value, and setup a proper write power prior to perform recording process. During the whole record period, a plurality of tracks are recorded using this write power for several dozens of seconds.
However, when a record task lasts for a long period, the temperature of optical disc is raised up. In ideal, the write power should be decreased in order to keep the temperature of optical disc in a proper range. But the write power only is setup before the record process, not adjusted during the record task by the conventional recorder. In other words, the write quality of the later part of the record task may be downgraded due to the heating temperature of the optical disc.
Accordingly, there exists a need of a method for adjusting write power when recording optical disc in order to maintain good write quality in the whole recording duration.